How will the armature current and the output power of a DC shunt motor change with increasing load?

If the load on the motor is increased, the armature rotation slows and back EMF is reduced, since back EMF is proportional to speed. With less back EMF voltage and a constant supply voltage (E), the net voltage increases. The increase in net voltage results in an increase in armature current.

How will the armature current and the output power of a direct current series wound motor change with increasing load torque?

As net voltage Enet = E − Eb. Since supply voltage E remains constant. As a result of this increased amount of net voltage, the armature current increases and consequently the torque increases. This increase in the amount of torque increases the speed and thus compensating for the speed loss on loading.

What happens to the armature current of DC shunt motor with increase in mechanical load?

In case of DC shunt motor, the flux per pole is considered to be constant, torque increases with the increase of load current. If the load current increases then the armature current also be increased and the speed slightly falls due to increase in voltage drop in armature.

How will the efficiency of a DC shunt motor change from no load to full load?

By changing the design, highest efficiency can be made at full load. At maximum efficiency, the I^2*R losses are approximately equal to the no-load losses. At higher load, the efficiency falls again due to increase of I^2*R losses with increase of current.

What is the relation between armature torque and armature current in DC series motor?

The torque in case of a dc series motor is proportional to the square of the armature current. This relation is parabolic in nature as shown in the figure. As load increases, armature current increases and torque produced increases proportional to the square of the armature current up to a particular limitation.

What is armature current in DC motor?

In the armature, an electromotive force is created by the relative motion of the armature and the field. When the machine or motor is used as a motor, this EMF opposes the armature current, and the armature converts electrical power to mechanical power in the form of torque, and transfers it via the shaft.

What is armature current?

In electrical engineering, the armature is the winding (or set of windings) of an electric machine which carries alternating current. The first is to carry current across the field, thus creating shaft torque in a rotating machine or force in a linear machine.

What happens when armature current increases?

With increased armature current maximum speed, could be controlled up to rated speed, from zero speed as V= Eb+IaRa, where V the rated voltage and Ia the rated armature current, Eb back EMF(Eb=OZNP/60A) produced at rated field current (If) and speed(N).

What will be the effect of armature reaction in performance of DC shunt motor?

This will cause distortion in main field flux which is called cross magnetising effect of armature reaction. The armature m.m.f. lags behind field m.m.f. with respect to the direction of rotation in case of motors and vice versa in case of generatos.